Implantable vascular access device

ABSTRACT

An implantable vascular access device includes a housing having an inlet, an outlet, an interior chamber defined therein and a valve positioned between the inlet and the interior chamber. The valve is subcutaneously manipulated between an open position, in which fluid can flow between the inlet and the interior chamber, and a closed position in which the valve occludes the inlet. The device may include any combination of multiple inlets, outlets and/or interior chambers. In the preferred embodiment, the housing includes two separate interior chambers suitable for the inflow and outflow of a typical hemodialysis procedure. A method for accessing a vascular structure is provided which includes the steps of subcutaneously implanting the device connecting one end of a cannula to the outlet of the device and another end of the cannula to a selected vascular structure. The valve of the device is manipulated to permit fluid communication between the inlet of the device and the selected vascular structure. A needle is introduced through the inlet opening to access the selected vascular structure.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to implantable vascular accessdevices used in the delivery and/or withdrawal of fluids to and from thebody and more particularly relates to a self-sealing device whichpermits intermittent vascular access.

[0003] 2. Description of the Prior Art

[0004] Conventional vascular access devices are surgically implantedunder the skin to allow for intermittent access to a selected vascularstructure, such as an artery or a vein, for introducing and/orwithdrawing fluids to and from the selected vascular structure.Typically, such devices generally include an interior chamber having anoutlet opening connected via a cannula to a vascular structure withinthe body and a penetrable membrane which serves as a cover for theinterior chamber of the device. The penetrable membrane or septum iscomprised of a material, such as silicone rubber, which automaticallyreseals itself after being penetrated by a hypodermic needle or a needleintroduced catheter.

[0005] In operation, a needle passes through the skin and through thepenetrable membrane into the interior chamber allowing fluid to beinjected into the chamber and expelled through the cannula into theselected vascular structure or, conversely, fluid may be withdrawn. Theadvantages of an implantable device over acute catheter proceduresinclude reduced infection, easier patient maintenance and improvedaesthetics. Typical implantable vascular access devices are shown inU.S. Pat. No. 5,318,545 to Tucker and U.S. Pat. No. 5,755,780 to Finch,Jr. et al.

[0006] The advancement of modem hemodialysis procedures have broughtwith it the development of vascular access devices for the purpose ofacquiring and returning large quantities of blood for passage through ahemodialysis unit. To facilitate adequate dialysis flow rates,relatively large diameter needles and/or catheters in the range of 14gauge or higher are required. A major drawback of conventional vascularaccess devices, particularly those used in hemodialysis procedures, isthe deterioration of the rubber membranes as a result of repeatedpenetration with such large gauge needles. Additionally, typicalvascular access devices provide for only one needle port resulting inchronic breach of the skin at the same location. This in turn results inincreased skin trauma and possible infection.

[0007] Accordingly, it is desirable to provide a vascular access devicewhich can withstand multiple insertions with a large diameter needle andwhich provides reduced skin trauma and easier patient maintenance.

SUMMARY OF THE INVENTION

[0008] It is an object of the present invention to provide a vascularaccess device which can withstand a high number of large gauge needleinsertions without deterioration.

[0009] It is another object of the present invention to provide avascular access device which is easily subcutaneously manipulated andwhich prevents the escape of fluids from the device.

[0010] It is yet another object of the present invention to provide avascular access device having multiple needle ports thereby reducing theskin trauma caused by repeated needle sticks at the same location.

[0011] It is still a further object of the present invention to providea vascular access device suitable for hemodialysis procedures whichincorporates two interior chambers into a single body.

[0012] In accordance with one form of the present invention, a vascularaccess device generally includes a housing having an inlet, an outlet,an interior chamber defined therein and a valve positioned between theinlet and the interior chamber. The valve is movable between an openposition, in which fluid can flow between the inlet and the interiorchamber, and a closed position in which the valve occludes the inlet.Preferably the valve comprises an elongate member having a through-holeformed therein which aligns with the inlet when the valve is in the openposition. One or both ends of the elongate member protrudes through thehousing and is palpable through the skin of the patient. The elongatemember is resiliently urged to its closed position by a spring and isopened by subcutaneously pressing the end of the member protrudingthrough the housing.

[0013] The present invention may include any combination of multipleinlets, outlets and/or interior chambers. In the preferred embodiment,the housing includes two separate interior chambers suitable for theinflow and outflow of a typical hemodialysis procedure. The devicefurther includes multiple inlets in fluid communication with eachinterior chamber. Several elongate members are moved simultaneously toan open position by a single push button protruding through the outersurface of the housing. Each elongate member includes through-holeswhich are aligned with respective inlets when the push button isdepressed to move the elongate members to their open position. When thebutton is released, a spring urges the elongate members to their closedposition thereby occluding the inlets. Each interior chamber is in fluidcommunication with an outlet which is connected to a selected vascularstructure by means of a cannula for permitting fluid communicationbetween the vascular structure and the interior chamber of the device.

[0014] A method for accessing a vascular structure is provided whichincludes the steps of surgically implanting a device as described above,connecting one end of a cannula to the outlet of the device and anotherend of the cannula to a selected vascular structure, subcutaneouslymanipulating the valve of the device for permitting fluid communicationbetween the inlet of the device and the selected vascular structure andintroducing a needle or a needle-introduced catheter through the inletopening to access the selected vascular structure.

[0015] A preferred form of the vascular access device, as well as otherembodiments, objects, features and advantages of this invention will beapparent from the following detailed description of illustrativeembodiments thereof which is to be read in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIGS. 1A and 1B are cross-sectional views of the vascular accessdevice formed in accordance with the present invention showing the valvein its closed and open positions, respectively.

[0017]FIG. 2 a perspective view of the preferred embodiment of thedevice shown in FIG. 1.

[0018]FIG. 3 is a cross-sectional view of the device shown in FIG. 2taken along the line 3-3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Referring to FIGS. 1A and 1B, an implantable vascular accessdevice formed in accordance with the present invention is shown. Thevascular access device 10 is designed to be surgically implanted underthe skin and generally includes a housing 11 and a valve 12. The housing11 and the valve 12 may be made from any suitable biocompatible materialpossessing sufficient hardness to resist being damaged or gouged byneedles or other devices which will be repeatedly inserted into thedevice. Plastic constructions are advantageous in that they areinexpensive to fabricate utilizing conventional molding techniques andare available in a variety of biocompatible materials. Surgical metals,however, are also suitable.

[0020] The housing 11 includes an interior chamber 13 formed therein,and an inlet 14 and an outlet 15 extending through an external surface16 of the housing and communicating with the interior chamber. Theoutlet 15 may be formed with a cuff 17 to facilitate connection to acannula 18. The opposite end (not shown) of the cannula is connected orgrafted to a selected vascular structure (e.g. an artery or a vein) in aconventional manner. The housing 11 also includes a peripheral rim 19having apertures 20 for securing the device to fascia underlying theskin by means of sutures threaded through the peripheral apertures.

[0021] The valve 12 preferably comprises an elongate member 21 having atransverse bore or through-hole 22 formed in a body portion 23 thereof.The elongate member 21 further includes a neck portion 24 foraccommodating a spring 25. To maintain the proper orientation of theelongate member 21 with respect to the inlet openings 14, the neckportion 24 and/or the body portion 23 is formed with a non-circularcross-section which prevents the elongate member from rotating whenfitted in close sliding relationship within a correspondingly sizedsupport hole 26 or 27 formed in the external surface 16 of the housing11. The opposite ends of the elongate member 21 are slidably supportedby and protrude through the support holes 26 and 27 of the housing 11.Sealing rings (not shown) may be provided on the elongate member 21 toprevent leakage from the support holes 26 and 27. The spring 25 is alsomade from a biocompatible material and is captured around the neckportion 24 between the internal surface of the interior chamber 13 andthe body portion 23 for resiliently urging the elongate member 21 to itsclosed position, i.e., to the right as shown in FIGS. 1A and 1B. Aretaining clip 28 is fixed to the protruding end of the neck portion 24to retain the elongate member 21 in its closed position within thehousing 11. Although a spring is preferred, other biasing devices, suchas internally molded magnets, may also be utilized for resilientlyurging the elongate member 21 to its closed position.

[0022] In use, the vascular access device 10 is surgically implantedsuch that it is entirely subcutaneous. In its normally closed position,the body portion 23 of the elongate member 21 blocks or occludes theinlet opening 14 thereby preventing fluid communication between theinlet and the interior chamber 13. When the protruding end of the bodyportion 23 is subcutaneously depressed, the elongate member 21 moves toits open position in which the transverse through-hole 22 aligns withthe inlet opening 14 thereby permitting fluid communication between theinlet opening and the interior chamber 13 through the elongate member.When the valve 12 is in its open position, a needle 29 or aneedle-introduced catheter may be percutaneously inserted through theinlet 14 into the interior chamber 13 to introduce or withdraw fluidfrom the selected vascular structure via the cannula 18. Once the needle29 is inserted, the needle will hold the elongate member 21 in its openposition thereby allowing the protruding end of the body portion 23 tobe released. Once the needle 29 is removed, the spring 25 willautomatically return the elongate member 21 to its closed position inwhich the inlet opening 14 is again occluded and blood reflux isprevented.

[0023] Referring now to FIGS. 2 and 3, a preferred form of theimplantable vascular access device 30 is shown. The multi-port device 30shown in FIGS. 2 and 3 includes a housing 31 formed with two separateinterior chambers 32, an outlet 33 in fluid communication with eachinterior chamber and a plurality of inlets 34. The housing 31 shown inFIGS. 2 and 3 includes three external access surfaces 35 each with apair of inlets 34 which communicate with a respective interior chamber32. However, any geometric configuration for the housing, such asadditional access surfaces, additional interior chambers or additionalinlets may be utilized.

[0024] The multi-port device 30 includes a valve which comprises threeelongate members 36 each having a spring 37 fixed at one end thereof anda push button 38 with a push plate 39 adjacent the other end. Theelongate members 36 are formed with transverse through-holes 40, asdescribed above, and are slidably supported in longitudinal bores 41formed in the housing. The springs 37 are captured between the elongatemembers 36 and the bottom walls 42 of the longitudinal bores 41 formedat one end of the housing 31. An end cap 43 is fixed to the opposite endof the housing 31 for retaining the push button 38 and the push plate39. The end cap 43 is formed with a recess 44 for retaining the pushplate 39 and a counter bored opening 45 through which the push button 38protrudes. The push button 38 is formed with a shoulder portion 46 whichis retained by the counter bored opening 45 so that the push button isheld within the end cap 43. The depth of the recess 44 allows the pushplate 39 to travel a predetermined distance when the push button 38 isdepressed.

[0025] Operation of the multi-port device 30 is similar to that asdescribed above. The springs 37 resiliently urge each of the individualelongate members 36 into their normally closed position in which theelongate members occlude the inlet openings 34. When the push button 38is subcutaneously depressed, the elongate members 36 are simultaneouslymoved to their open position by the push plate 39 (i.e., to the right asshown in FIG. 3) wherein the transverse through-holes 40 of the elongatemembers align with respective inlet openings 34. Again, the elongatemembers 36 may be formed with non-circular cross-sections so that theirproper orientation with respect to the inlets 34 is maintained. Once theelongate members 36 are moved to their open position any one or more ofthe inlets 34 may be accessed with a needle for withdrawing orintroducing fluid through the interior chambers 32. In a typicalhemodialysis procedure, an infusion needle is inserted through an inlet34 into one of the interior chambers 32 and an aspiration needle isinserted through another inlet into the other separate chamber. Theinterior chambers are in fluid communication with at least one selectedvascular structure by means of the cannulas 47, as described above.Again, once the needles are inserted the push button 38 may be releasedand upon removing the needle the springs 37 automatically urge theelongate members 36 back to their normally closed position. Preferably,needles should be inserted in corresponding pairs of inlets 34 on thesame access surface 35 so that when the push button 38 is released theremaining elongate members not being accessed will return to theirclosed position.

[0026] As a result of the present invention, a multi-port vascularaccess device is provided which can withstand numerous needle insertionswithout deterioration. Additionally, the multi-port design allows forneedle insertion at different locations on the skin thereby allowing theskin more time to heal before reinsertion of a needle. Furthermore, thedual interior chamber design of the present invention is particularlysuitable for hemodialysis procedures requiring simultaneous inflow andoutflow.

[0027] Although the illustrative embodiments of the present inventionhave been described herein with reference to the accompanying drawings,it is to be understood that the invention is not limited to thoseprecise embodiments, and that various other changes and/or modificationsmay be effected therein by one skilled in the art without departing fromthe scope or spirit of the invention, and it is intended to claim allsuch changes and/or modifications as fall within the scope of theinvention.

What is claimed is:
 1. A surgically implantable device for permittingintermittent vascular access simultaneously through a plurality ofaccess sites comprising: (a) a housing having two or more inletopenings, two or more outlet openings, and an interior conduit definedtherein, between said inlet openings and said outlet openings; (b) twoor more manipulatable housing valves comprising elongate memberspositioned between said inlet openings and said outlet openings movablebetween an open position, in which fluid communication is permittedbetween said inlet openings and said outlet openings and a closedposition in which said elongate member occludes fluid communicationbetween said inlet openings and said outlet openings; (c) at least onepush plate adjacent to at least one of said valves; and (d) at least onepush button juxtaposed to at least one push plate, a portion of which isexternal to said housing to allow subcutaneous manipulation of saidvalves.
 2. The device as defined in claim 1, wherein said elongatemember includes a transverse bore formed therethrough, said borealigning with said interior conduit when said elongate member is in saidopen position for permitting fluid communication between said inletopening and said outlet opening.
 3. The device as defined in claim 1,further comprising a biasing device adjacent said elongate member forresiliently urging said elongate member to said closed position.
 4. Thedevice as defined in claim 3, wherein said biasing device comprises atleast one spring.
 5. The device as defined in claim 3, wherein saidbiasing device comprises a compression chamber.
 6. The device as definedin claim 1, further comprising at least one cannula having a proximalend connected to one of said housing outlet openings and a distal endconnectable to a selected vascular structure.
 7. The device as definedin claim 6, wherein said distal end of said at least one cannulaincludes a manipulatable distal valve positioned adjacent a cannulaoutlet for selectively permitting fluid communication between saidhousing outlet opening and said cannula outlet.
 8. The device as definedin claim 7, wherein said distal valve is connected to one of saidhousing valves whereby manipulation of said housing valve simultaneouslyactivates said distal valve.
 9. The device as defined in claim 7,wherein said distal valve comprises a tubular member having an outerwall and an interior passage, said tubular member being movable withinsaid cannula between an open position, in which fluid communication ispermitted between said housing outlet opening and said cannula outletthrough said interior passage of said tubular member, and a closedposition, in which said outer wall of said tubular member occludes saidcannula outlet thereby preventing fluid communication between saidhousing outlet opening and said cannula outlet.
 10. The device asdefined in claim 9, further comprising a biasing device adjacent saidtubular member for resiliently urging said tubular member to said closedposition.